Shared mailbox not shown in Shared folder on On-premised Exchange server

Frequent Contributor



I created a user account and assigned Office 365 license to it. It is shown in the Mailbox on both of On-Premises Exchange server and online Office 365. Then I converted the mailbox to Shared mailbox online, on Office 365, it is moved to Shared folder, however in On-Premises Exchange, it is still in mailbox folder although the sync is successful.


How can I move the shared mailbox to Shared folder in On-Premises Exchange server?


Thanks in advance!  

4 Replies
Your experiencing having duplicate mailboxes, it happens often when you assign licenses to someone that has onprem mailbox then you enable their license it'll create a mailbox in 365 and pretty much duplicating it.

Here is a blog post about it. Be careful to see what mailbox your user is using, you may need to export one of them first before doing this so you do not lose data etc.

If you want on-premises to recognize this object as a shared mailbox, the proper workflow would be to migrate it on-premises, convert to shared, then move it back to O365. Or you can manually change the relevant attributes on-premises, although this is not a supported solution.


That's assuming you don't have a duplicate mailbox as Christopher suspects :)

Hi Christopher,


Thank you for your rely. I went through the article but not feel confident to follow it. I am contacting MS and have their support to help me.